1. Field of the Invention
The present invention relates to a method of fabricating a pixel structure, and more particularly to a method of fabricating a pixel structure in which an alignment slit is formed.
2. Description of Related Art
In a method of fabricating a conventional pixel structure in a liquid crystal display (LCD) panel, five photomasks are required in most cases. The first photomask is used to define patterns of a first metal layer for forming scan lines and gates of active devices. The second photomask is used to define a channel layer and an ohmic contact layer of the active devices. The channel layer and the ohmic contact layer are collectively referred to as a semiconductor layer. The third photomask is used to define patterns of a second metal layer for forming data lines and sources/drains of the active devices. The fourth photomask is used to pattern a dielectric layer above the second metal layer. The fifth photomask is used to pattern an electrode material layer for forming pixel electrodes.
Besides, consumers are in pursuit of large-sized LCD panels and wide-view-angle performance. At present, one of the most common LCD panels with wide-view-angle performance is a multi-domain vertical alignment (MVA) LCD panel in which alignment slits are disposed to tilt liquid crystal molecules in different regions towards various directions, thereby achieving the wide-view-angle performance. When the fifth photomask is used to pattern the electrode material layer as stated above, the pixel electrode equipped with the alignment slits can be formed.
Nonetheless, costs of the photomasks are rather high, and therefore the number of photomasks becomes a decisive factor of the manufacturing costs. Additionally, with the development of the large-sized LCD panels, dimensions of photomasks are increased as well, thus giving rise to an increase in the costs of the photomasks. Hence, manufacturers are dedicated to the reduction of the required number of photomasks.